While that is reasonable if your being drawn to Sargeras sword and seem to think it related to it. Assuming it would be related to the world soul should have been one first thought.
Again, the idea that Thrall was not informed the Sword was aiming for the world soul sounds like a bad plot point. Magni/the heroes who were using the Heart of Azeroth, didnt bother to tell anyone what Sargeras was aiming for?
Basically.
Some others would be going soâŚthe Lysergic acid diethylamide flashback finally kicked in.
Skyrim did this better. We have cicero set up the mother listener lore.
then we hear our sweet motherâs voice. and then cicero says âlucky!â.
Iâm still on the fence about that line being foreshadowing for him targeting something else. If it comes out that Thrall was just ignorant of the world soul, I wouldnât be surprised though, itâd just be more Blizzard brand story telling
Oh. Thatâs interesting. It looks kind of similar to Xeraâs core Lightâs Heart but huge.
Funny enough is that might be a naruu that crashed centuries ago. Maybe the Arthai could be lightforged. 
Sargerasâ goal was never to âCorruptâ Azeroth â it was to destroy her, to prevent her from being corrupted by the void. That was the whole gimmick of him releasing the leagues of Demons from the world-prison he built & founding the Legion.
However, itâs not so far fetched to think Sargeras was aiming at someone particular other than Azeroth herself â It couldâve been something that couldâve led to her corruption after the imprisonment he potentially saw coming just as it was in the final moment.
All the major NPCs acting like they donât know who the voice belongs to is really corny.
The idea is itâs maybe not the World Soul not that characters are unaware of the World Soul.
To be fair itâs probably a bad idea to make assumptions like that when things like old gods can invade peopleâs minds as well.
We know from the trailer that Alleria is hearing whispers from the Void.
There have been a lot of voices broadcasting whispers and visions over the past couple of decades and I canât remember the last time time it was a good thing.
Even if the idea that it is worldsoul of Azeroth is on the table, they have good reason to be careful and skeptical ⌠and if it is Azeroth, they still have good reason to be careful.
Yep. Neltharion literally was imitated in Aberrus.
The most logical explanation to me would be that itâs not actually Azeroth at all. Itâs an entity mimicking her in order to lure us inward.
He was trying to turn her to fel.
Magni is the only one who can hear Azeroth, so Thrall and Anduin wouldnât assume it is her. Also the last time multiple people heard whispers it was an Old God, so it makes sense why they wouldnât assume itâs Azeroth but also want to confirm if itâs an Old God or not whispering to them first.
Thrall can also hear the elements, and I believe (?) Anduin can or could hear the light?
I mean, Thrall mostly has an excuse. He was on Draenor until Saurfang called on him to help out with Sylvanas, so he had bigger things going on than catching up on cosmic gossip (as did the adventurers, honestly), pretty much immediately got taken to the Shadowlands and was stuck there for a couple years, and by the time he came back to Azeroth Magni was MIA, Khadgar was in Karazhan and most anyone else who actually knew about it were either dead, missing or simply didnât think it was that important to talk about anymore, given other revelations.
Werenât people surprised that Anduin knew about Bolvar being alive back when Shadowlands started or something?
No, he wasnât.
Fel is described as being fatal to world souls & extremely harmful to Titans (Sargeras is rather the exception but not the rule). Which is why Sargeras & his former-buddy Aggramar were went out to deal with fel-beings & demons who utilised its power and spread its domain.
Source: Chronicles 
Thrall an anduin stopped paying attention to WoWâs story years ago. Donât worry they will watch some Nobbel videos to catch up before the next expac.
Honestly so have like ~90% of the people who complain about WoWâs story, or not liking a character. Itâs like they all just watch the cutscenes and are like âI donât like this, why isnât this thing happening that happened in the quest text that nobody readsâ.
Chronicles is no longer canon and it is that Titans were weak against it. Also donât forget Argus was a world soul who was corrupted by him when he took over that planet. They also went to find out why beings of cruelty and chaos kept returning after they defeated them over and over.
Then in the Legion raid he was trying to âclaimâ Azeroth and didnât stab the planet until the other titans started pulling him away. If he had wanted to destroy the world he could have done it from the get go.